Consider removal of deprecated elements as compatible

I'm using openapi-diff quite successfully to avoid accidental changes in the API (and therefore introducing a breaking change). We use it as a part of our pipeline.

The current struggle is: that sometimes one wants to introduce a breaking change (like the removal of obsolete API).
My initial idea would float around a two-step process:

• marking an element ad deprecated (keeping compatibility)
• removing the deprecated element

To do that, when processing the list of ChangedOpenApi#getChangedElements I'd need to know if the particular element is deprecatable and decide if the change is incompatible or not.

That looks to me like another SPI but I'm not sure if it's the direction. I know it's currently not possible and I'm not even sure if the direction of my thought even makes sense.

まず ChangedOpenApi#getChangedElements と、openapi-diff が現在削除を非互換として分類する方法を調査します。アプローチを決定する前に、既存の拡張ポイントと issue で提案されている SPI のアイデアを確認します。Done では、既存の breaking-change チェックを維持しながら、非推奨要素の削除を互換として扱う明確な方法を提供する必要があります。